Gas pilot burner with annular flame port



Jan. 24, 1950 w.. RIEHL GAS PILOT BURNER WITH ANNULAR FLAME PORTOriginal Filed July 12, 1944 mmw 1,.

Patented Jan. 24, 1950 GAS PILOT BURNER WITH ANNULAR FLAME PORT WilliamL. Riehl, Marcy, N. Y., a'ssignor to Union Fork .8; Hoe Company,Columbus, Ohio, 'a corporation of 'Ohio Original application July 12,1944, Serial No. 544,529. Divided and this application October 5, 1945,Serial No. 620,515

v2 Claims. (Cl. 158-115) This invention relates to combustion systemsand is particularly useful in those systems in which fluid fuel isburned under subatmospherio pressures. 1

Another object .of the invention is to provide an improved combustionapparatus which will be extremely elficient in operation.

Another object of the invention is to provide an improved combustionapparatus in which the fuel will automatically be ignited.

Another object of the invention is to provide an improved combustionapparatus in which the ignition device will be well-protected.

Another object is to provide an improved oombustion apparatus in whichthe ignition device will be in position to insure quick and effectiveignition of fuel when it is admitted.

.Another object is to provide an improved combustion apparatus having apilot burner which will prevent accumulations of dirt at its outlet andat the ignition device.

Another object is .to provide an improved combustion apparatus having apilot burner which may be easily and accurately assembled.

Another object is to provide an improved combustion apparatus .having :a.pilot burner which will produce a hollow cylindrical flame.

Other objects will hereinafter appear. This application is a division ofmy .co-pending application, Serial No. 544,529, 'filedJuly 12, .1944,

now abandoned.

Theinvention will be better understood from the description of onepractical embodiment thereof, illustrated :in the accompanying drawings,in which:

Figure 1 is a fragmentary elevational view,

parts being broken away and shown in section,

of a combustion control system, together with parts of a combustionchamber and burners;

Figure 2 is a central, vertical, sectional view of the pilot andignition mechanism of Figure 1, shown to an enlarged scale; and,

Figure 3 is 'a transverse sectional view taken on the line III--III ofFigure 2.

The combustion system of this application is especially useful forburning fuels at .subatmospheric pressures, and will be described inc0njunction with an apparatus for this purpose. will be understood,however, that features of it may readily .be adapted to combustion athigher pressures, up to and even above atmospheric.

.In Figure 1 the combustion apparatus is shown as including a burner I,positioned within a hermetically sealed combustion chamber 2, from whichproducts of combustion are exhausted by means of a fan or blower 3,driven by an electric motor 3.

'Fuel and air are drawn into the burner by means of the subatmosphericpressure or partial vacuum thus induced in the combustion chamber, the.fuel being supplied 'by a conduit 5 from any suitable source, such, forinstance, as a main delivering gas under pressure, while the airisadmitted to the system as will be more fully hereinafter described.

The pipe 5 is threaded into the end of a valve body .6, :in general ofthe shape of an ordinary globe valve, having a .seat 1 which may beengaged by a valve consisting .of a stem .8, a head 9,

' and a gasket or washer I 0 of soft leather or the like, the valve headbeing urged toward its seat by a compression spring H interposed betweenit and a 'plug l2 threaded in the valve body.

The valve stem projects through an aperture in the lower .side of thebody, being sealed to the body by means of a flexible diaphragm I3, themargin of which is clamped between a flange l4 formed on the body and asimilar flange l5 of a diaphragm housing I6.

From the valve body 6 a pipe or "conduit l1 extends to a second fuelvalve body 18, in all essential respects similar to that just abovedescribed, and having a valve seat 19, a valve comprising a head 20, astem 2|, and a washer 22, there being also a valve seating compressionspring 23 and a closure plug 24.

The valve stem is sealed by a'flexible diaphragm 25 with its marginclamped between 'a flange 26 on the valve body l8 and a tubularextension 2! of .a diaphragm housing 28.

From the valve body I8 a pipe or conduit extends to an orifice member30, shown as an adjustablevalve or stopcock, which in turn communicateswith an angle 3| secured to one arm of a T fitting 32, the other arm ofwhich is connected by a pipe 33 to the burner I.

The stem or third branch or the T has secured to it an air inlet controldevice, shown as an angle valve 34.

The diaphragm housing l6 carries on its interior a lever 35 pivoted tothe housing as indi cated at 36 and contacting the lower end of thevalve stem 8. The free end of the lever is pivoted near the center of aplate 31 secured to the upper surface of a diaphragm 38, the edge ofwhich is "clamped against the housing 16 by a cover 39.

.A pipe 49 leads from the interior of the diaphragm housing I6, thispipe being provided with two branches, one of which communicates throughan orifice controlling member shown as a valve or stopcock M with theinterior of the conduit 33 and the other of which communicates throughan orifice controlling member illustrated as a valve or stopcock 42 withthe interior of conduit 29.

The second diaphragm housing 28 is provided with a lever 43, pivoted atone end 44 to the housing, and adjacent this end engaging the lower endof the valve stem 2| and having its free end in pivoted engagement withthe center of a plate 45 carried by a flexible diaphragm 4B clampedbetween the margin of the housing 28 and that of a cover 31.

The space above the diaphragm 46 Within its housing is in communicationwith a tube 48 which extends to a magnetically controlled valve 49 andthence, as indicated at 59, to the interior of the combustion chamber 2.

A tube extends from conduit I! to a fitting such as a T, 52, having astopcock 53 by which air may be admitted to the tube 54 leading to thepilot burner, this being indicated generally at 55 in Figure l and shownto-an enlarged scale and in greater detail in Figure 2.

A thermocouple 56 is positioned within the combustion chamber adjacentthe outlets of the burner andof the pilot burner 55 and from thethermocouple leads 51 extend to the magnetic valve 49.

It has been found, in practice that a single thermocouple furnishesadequate current for the actuation of this magnetic valve.

Connected to the conduit 29 is a pressure operated switch consisting ofa housing 89 having a I;

flexible diaphragm Ill which carries a conductor '1'! arranged to bridgetwo stationary electrical contacts '82 carried by and insulated from thehousing cover or bottom '13, these contacts being in a circuit includingwires 74, and 15, a sec ondary T! of a transformer, and the electricalresistance coil 19 of the igniter coil in the pilot.

The primary '19 of the transformer is connected by conductors 80 througha plug 8! to an ordinary 110 volt A. C. lighting circuit or the like.

The igniter and pilot burner, as best seen in Figure 2, consists of ahollow shell made of two telescopically arranged tubular members, theouter one of which 82 is reduced in size at its lower end 83 and sealedto the inner end 85 as by welding or brazing.

The upper end of the outer tubular member is also reduced in diameter atB5 and the space between this and theinner member contains a corrugatedmetal strip 83 which divides the space between the tubular members intoa number of relatively small axially extending portions which precludethe passage of flame to the interior of the pilot burner.

The outer surface of the outer tubular member 82 is threaded andprovided with nuts 81 by which it is clamped tightly through the wall ofthe combustion chamber 2.

Within the inner tubular member is a cylindrical insulator 8B of suchmaterial as porcelain having two parallel axially extending apertureswhich receive the ends of the helically coiled resistance wire '48,these ends being connected to leads 89 which pass through the bottom ofthe insulator into an insulating block 99 where they are secured as byset screws 9 I, the block 99 being held to the tubular members by athreaded centrally perforated cap 92 which leaves the end of the blockexposed. Y

A conventional electrical plug 93 having two 4 contact prongs may beconnected with the block 99 at the end of the pilot for supplyingcurrent to the coil 73 of resistance wire.

It will be obvious that one side of the resistance coil 78 could begrounded if desired, so that only a single conductor need be connectedwith the other end thereof.

It will be noted that the coil of resistance wire it is looped around sothat it projects beyond the upper end of the porcelain insulator 88, andthat this end is retracted below the upper ends of the telescopictubular members 82 and 84, so that a part of the coil extends slightlyabove these ends only.

This insures the heated loop of the coil being in close proximity to themixture of air and gas which emerges from the tubular members, andguarantees ignition of the same.

However, once the pilot flame is ignited, it is drawn upwardly generallyin an axial direction, in the form of a hollow cylinder, the spacewithin this cylinder having a reducing atmosphere which surrounds thecoil of ignition wire 18 and protects it from oxidation.

Gas is supplied to the pilot burner at full line pressure as long as thevalve 55 is open and valve 18 is closed, as is the case at the start ofthe cycle of operation, but as soon as the second valve It opens and gasis admitted to the main burner, the pressure supplied to the pilotdrops.

The motor i actuating the blower or exhausting means is supplied withcurrent by conductors 94, connected with a suitable source of currentsupply, in one of which is interposed a pair of relay contacts 95. Thecoil 38 of the relay is supplied with current through a transformer 91,the primary of which is connected across lines 94, and the secondarycircuit of which includes both coil 95 and a thermostat 98 positioned inthe room or space which it is desired to be heated, so that the motor isactuated whenever heat is required, and is stopped whenever theneed forfurther heat ceases.

It will be apparent that atmospheric air pressure is exerted upon theunderside of each of the diaphragms and when a sufficient degree ofsuction exists on the upper side of the diaphragms, this air pressurewill move them, respectively, upwardly, the motion being controlled byand in accordance with the reduced pressure which obtains on their uppersides.

The apparatus above described operates as follows:

Assuming that the apparatus is out of operation, and that thetemperature of the space which is to be heated then drops sufiicientlyto require an additional supply of heat, the contacts of thermostat 93close, sup-plying current to the motor t which drives the blower 3,exhausting the contents of the combustion chamber and producing apartial vacuum therein.

This partial vacuum withdraws the contents from conduit sections 29, 30,Si, 82 and 33, also removing any traces of fuel, products of combustion,or the like, which may have remained within the combustion chamber 2.Fresh air is drawn in through valves 34 and 53 and thoroughly scavengesthe interior of the apparatus, making it certain that there is no fuelleft in such concentrated or undiluted quantities as to be eithercombustible or explosive.

The suction is precluded from exhausting the space within diaphragmhousing 28 as this space is vented through the electromagnetic valve 49.

The suction, therefore, may only raise diaphragm 38 and diaphragm 10,the first of which opens valve 3, permitting gas at the pressureexisting in the main to pass to valve 18 and also to pass through pipe5| to the pilot.

The raising of diaphragm bridges the stationary contacts 12 supplyingigniting current to the coil of resistance wire 18 which becomesincandescent and ignites the gas which is now drawn through the pilot bythe suction of the blower.

After the pilot has been ignited, the heat from its flame generates acurrent in thermocouple 56 which energizes the magnetic valve 49permitting the suction to exhaust through pipe 48, the space within thediaphragm housing 28, and thus to raise the diaphragm 46, opening valveI8.

The raising of this valve, of course, permits gas to pass into conduit29, through orifice member 33, and thence through conduit ports 3|, 32,and 33 to the burner I, the fuel being mixed after passing through the T32, with air entering the valve 34.

The gas is admitted to conduits 29 and 33, the pressure within theseconduits rises and permits a slight backflow through orifice members 4|and 42 into pipe 49, reducing the suction on the upper surface ofdiaphragm 38 and permitting valve 6 to partially or completely close,depending on the modulated pressure supplied to its diaphragm.

This increase in pressure also permits dia phragm 10 to drop, breakingthe circuit between the contacts 12 and so discontinuing the supply ofcurrent to the igniting coil 18 of the pilot.

When suflicient heat has been generated to actuate the thermostat 98,the motor 4 is stopped, the pressure in the combustion chamber andconduits rises, and all three diaphragms drop to their lowermostpositions, closing both valves and interrupting the circuit through theelectric contacts.

Gas which has already passed through valve 6 rises through the pipe 5|to the pilot burner and is consumed at this point as long as a sumcientconcentration to support combustion is render coil 18 incandescentbefore any gas is admitted to the main burner, and simultaneously asmall amount of gas will be delivered through pipe 5| to the pilot, tobe ignited and maintain combustion at this point.

It will be noted that pipe 5| is threaded into pipe l1, so that thispipe receives fuel under the pressure which obtains between the two fuelvalves.

It will be understood that pipe 29 is connected to pipes 40 and toorifice controlling member 30.

In the embodiment above described, the control is such as would besuitable for a single combustion device operated independently of anyothers, and havingits own individual pressure exhausting blower and roomthermostat 38 However, this system of combustion can be used toconsiderable advantage in places where a. plurality of units arenecessary, and several of these units may be connected to a singlecommon pump or blower 3, which may be caused to operate continuously aslong as there is any requirement for heat from any of the units.

Those units which are not required to furnish heat at any given time maybe turned off and may be ignited either automatically or manually whenthe temperature of the spaces with which they are associated fall to anypredetermined point.

While the embodiment illustrated is shown as operating in a single unit,at pressures below that of the atmosphere, the atmospheric pressureitself on the exposed surfaces of the diaphragms being utilized as theforce for opening the valves or closing the electrical contacts, as thecase may be, it will be apparent that the apparatus may be one of aseries of units, as described in the above mentioned parent applicationor that it may be used advantageously in operating with pressures higherthan that of the atmosphere. This would only require connecting thesource of higher pressures to one side of the diaphragm.

'While I have described the illustrated embodiment of my invention insome particularity, obviously many others will readily occur to thoseskilled in this art, and I do not, therefore, limit myself to theprecise details shown and described herein, but claim as my inventionall embodiments, variations, and modifications coming within the scopeof the appended claims.

I claim:

1. A pilot burner comprising two generally coaxial tubular membershaving their ends lying substantially in a given plane to form agenerally tubular outlet opening, means supplying fuel and air to thespace between said tubular members, an igniter positioned within theinner of said tubular members and projecting slightly beyond the planeof their end surfaces, and a corrugated sheet metal spacer between theoutlet ends of said tubular members dividing the space between them intoa plurality of small outlets.

2. A pilot burner comprising two generally coaxial tubular membershaving their ends lying substantially in a given plane to form agenerally tubular outlet opening, means supplying fuel and air to thespace between said tubular members, an igniter positioned within theinner of said tubular members and projecting slightly beyond the planeof their end surfaces, a refractory insulator within the inner tubularmember, a resistance wire projecting from the end of the insulatorbeyond the plane of the ends of the tubular member, and havingconductors extending through the insulator and connected to a source ofelectricity.

WILLIAM L. RIEHL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 686,625 Machlet Nov. 12, 19011,198,006 Chance Sept. 12, 1916 1,940,127 Herthneck Dec. 19, 19331,961,933 Irwin June 5, 1936 2,241,295 Clark May 6, 1941 2,340,899 RayFeb. 8, 1945 2,384,836 Holthouse Sept. 18, 1945 2,385,699 Fox Sept. 25,1945 2,407,517 Ray Sept. 10, 1946

